DESCRIPTION (Applicant's Description): Oxidative DNA damage induced by reactive oxygen species has been associated with aging and age-elated diseases, as well as several forms of human cancer. 8-Oxoguanine is a lesion that has been used as a marker for oxidative DNA damage. 8-Oxoguanine has been shown to be mutagenic in vivo and in vitro. Recently, mogg1, a murine 8- oxoguanine-DNA repair enzyme was cloned and over expressed in transgenic animals. Although extensive information has been accumulated on the substrate specificity and the repair mechanism of mogg1 and its isoforms, there is little information regarding their biochemical properties, regulation during the cell cycle and subcellular distribution in cells growing under normal and oxidative stress conditions. Similarly, there is little information regarding the intranuclear distribution of ogg1 and its molecular relationships with chromatin and structural components of the nucleus. We propose to address these questions by raising monospecific antibodies directed against purified b a c terially-expressed wild-type recombinant mogg1. We will use these a n t i b odies to determine the subcellular localization of mogg1 and biochemically characterize nuclear and cytoplasmic pools of the enzyme derived from mammalian tissue culture cells as well as the liver of wild-type and transgenic mice over expressing ogg1. We will also characterize the induction of oxidative DNA damage in nutrient deprived cells by determining whether levels of 8-oxoguanine correlate with the synthesis of ogg1 and heat shock proteins and evaluating the cell cycle-dependent regulation of ogg1. Finally, we will colocalize 3-oxoguanine nuclear "hot spots" with ogg1, chromatin and structural protein components of the nucleus in tissue culture cells and tissues from wild-type and transgenic mice over expressing mogg1.